Internal comparison standard for abdominal diffusion-weighted imaging.

Area of Science:

• Radiology
• Medical Imaging
• Oncology

Background:

• Standardization of abdominal diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) measurements is crucial for reproducibility.
• Accurate differentiation between malignant and benign abdominal lesions using ADC requires reliable internal comparison standards.

Purpose of the Study:

• To identify optimal internal comparison standards for DWI to normalize ADC measurements.
• To enhance the accuracy of differentiating malignant and benign abdominal lesions.

Main Methods:

• Retrospective analysis of 97 abdominal lesions in 89 patients with histopathological confirmation.
• Assessment of seven normal body parts/contents as potential internal references for ADC normalization.
• Statistical analysis including interclass correlation coefficients (ICCs), coefficient of variation (CV), and receiver operating characteristic (ROC) analyses.

Main Results:

• Normalized ADCs were significantly lower for malignant lesions compared to benign lesions (P < 0.001).
• Excellent ICC values were observed for all tested internal references.
• Normalized ADCs using normal parenchyma (AUC, 0.808) and CSF (AUC, 0.80) demonstrated higher diagnostic accuracy than lesion ADCs (AUC, 0.756 and 0.76, respectively) for differentiating lesion types.

Conclusions:

• Normal parenchyma within the lesion-detected organ is a suitable internal comparison standard for abdominal DWI.
• Cerebrospinal fluid (CSF) can be utilized as a generalizable in-plane reference standard for DWI analysis.